1. Field of the invention
This invention relates to a continuous flow instrument, such as a continuous flow endoscope, which may be used as a hysteroscope or cystoscope and more particularly relates to a continuous flow cystoscope having an outer sheath which has a hollowed-out central area which terminates in a distal end having an elongated fenestra and a means for defining an inner member which is located within the hollowed-out central area wherein the means defining the inner member includes means for defining an inner member channel having a first passageway receiving a telescope and a second passageway for passing a working tool. The inner member channel terminates in a distal end having an irrigation inlet. The inner member further includes means defining an elongated lip. The inner member is spaced from the inner surface of the outer sheath to define a fluid passageway for irrigant outflow and the elongated fenestra of the outer sheath and the elongated lip of the inner member cooperate to define a fenestra channel having an irrigation outlet. The fenestra channel communicates with the liquid passageway. In a procedure, irrigation fluid is passed to the operative site through the inner member channel and through the irrigation inlet. Irrigation fluid is removed from the operative site by the irrigation outlet, which passes the fluid through the fenestra channel into the fluid passageway to an outlet port at the proximal end of the outer sheath. The flow path traversed by the fluid is along a path having reduced fluid turbulence at the irrigation inlet and operative site. The second passageway may be used to pass a working tool such as a laser fiber for the incision, excision, ablation and hemostasis of the lower genitourinary tract including prostatic tissue.
2. Description of the Prior Art
Continuous flow resectoscopes are well known in the art. U.S. Pat. No. 3,835,842 discloses a continuous flow resectoscope for use in urology. Continuous flow resectoscopes have been used for other surgical procedures. An article entitled, The Use of the Resectoscope in Gynecology, by Richard A. Auhll, appeared at pages 91 through 99 in the Oct. 11, 1990 issue of the Biomedical Business International (the "Auhll Reference") describes the use of the CIRCON ACMI uterine resectoscope system for gynecological procedures. The Auhll Reference discloses that the use of a continuous flow electrical resectoscope system (CFR) includes a continuous flow irrigation system. Multiple concentric sheaths allow continuous and simultaneous inflow and outflow of non-conducting irrigating solutions to the operative site so that the surgeon has a clear view through the solution. It is known in the art that the means for passing fluid into the uterus in order to distend the same cannot have the fluid pressure exceed an intrauterine pressure of 90 mm of mercury. If the fluid pressure exceeds 90 mm of mercury, then the fluid is absorbed into the tissue of the uterus which is undesirable in performing an OB-GYN procedure.
In addition, the continuous flow irrigation system provides sufficient flow and pressure to distend and expand the uterus to enable the surgeon to perform the desired procedure. Such a system is referred to as a Uterine Resectoscope System. The Uterine Resectoscope System is used for three operative procedures: (i) Myoma resection; (ii) endometrial ablation; and (iii) cynical septa dissection.
The presently known continuous flow resectoscope and continuous flow hysteroscope systems generally pass an irrigating fluid through the center of an inner sheath and out of the distal end to irrigate the operative site. Fluid is removed from the operative site by passing the fluid through a passageway formed between the outer surface of an inner sheath and the inner surface of an outer sheath. Typically, fluid flow is obtained by positioning the source of fluid at a predetermined height in the operating room. For example, positioning a bag of saline fluid at approximately 1 meter above the operating table will produce 75 mm of mercury head pressure. At a height of 1.4 meter produces approximately 103 mm of mercury pressure at the outlet of the source. The pressure drop through the various tubing and through the resectoscope drops the pressure to a range of 60 mm of mercury to 90 mm of mercury at the distal end of the hysteroscope.
Continuous flow hysteroscopes are known in the art and comprise an outer sheath having an outer surface, an inner surface and a hollowed out central area extending along a central axis. The outer sheath has an outer surface, an inner surface and a hollowed out central area extending along a central axis. The outer sheath has a distal section which terminates in a distal end and means are located at the distal section for defining around the outer surface of the sheath a plurality of openings which extend between the outer surface of the sheath and the inner surface. The plurality of openings pass fluid exterior to the distal section therethrough and into the hollowed out central area. The continuous flow hysteroscope further includes means defining an inner member positioned within the outer sheath for defining a fluid passageway which is adapted to pass irrigation fluid passed from the operation site through the plurality of openings into the fluid passageway and out of an outlet port located at the proximal end of the outer sheath. The inner member includes means defining a first channel and second channel which are adapted to receive a telescope and a working tool, respectively. An additional accessory or working channel may also be provided. The first and/or second channel pass irrigation fluid from an inlet port, through the inner member and out of the distal end of the inner member to the operative site. The irrigation fluid is passed over the distal end of the telescope and traverses a flow path to the plurality of openings which are located in substantially the same section as the distal end of the telescope.
An example of such a continuous flow hysteroscope is CIRCON ACMI Catalog No. GY8-CFH, Continuous Flow Hysteroscope.